Get your GH serum levels tested.
Why would you pin something that you "suspect the authenticity" of? (Actually, most have done the same thing with one product or another.)
You could very well be injecting yourself with drywall dust or Zyklon B.
I know you paid a lot for it so you want to believe you got what you paid for. Same reason most of the rest of us have pinned "suspect" products.
Myself, I stopped using GH altogether because, honestly most of what's out there seems to be completely fake or grossly underdosed no matter where it comes from.
If you can pin the gear WTF is wrong with a blood test? Close your eyes and think of England or stare at the tits of the girl taking your blood.
Just don't eat before you go. That way you don't blow lunch.
Bottom line, no one here can tell you if your GH is authentic or not.
Pictures of the GH and can get you feedback on the likelihood of it being authentic or not but that should have been asked BEFORE you started using it.
Get your levels tested and then you'll know for sure.
If you do decide to get tested be sure to follow the protocol.